Video in chapters out of sync

[kevmor]

Viewing chapters in the inbuilt player shows correct thumbnail and start of video.
But once the DVD is made, the thumbnail shows correctly but the video is out by 5-6 seconds, sound and video is still in sync.

EG. Video shows person walking from a door on the left of the room to a door on the right. Thumbnail shows the left hand door correctly, but the video shows the person is now at the right hand door.

Any suggestions why the 5-6 second jump in video once DVD has been made.